Accumulation of 2HG to high levels in tumors can cause metabolic and non-metabolic dysregulation and malignant transformation.15 Unlike IDH-mutant leukemias whose increased 2HG may be found in the blood, IDH-mutant gliomas have normal blood levels and efforts to detect 2HG have thus far centered on imaging predominantly with proton magnetic resonance spectroscopy (MRS). This evidence concerns the gene IDH2 and central nervous system cancer.